The field concerns an inflatable convective pad is adapted to be deployed under a person in connection with surgery.
Warming a person during surgery affords clinical benefits, including prevention or treatment of hypothermia, encouragement of immune system function, and promotion of wound healing. An inflatable blanket is used to warm a person perioperatively. Such a blanket, when inflated with heated air, warms the person principally by convection of warmed air through the blanket, although conduction and radiation of heat from the blanket also contribute to warming.
However, blanketing a person for warming may interfere with particular surgical procedures. For example, during cardiac surgery access to the thorax, groin and extremities is necessary when blood vessels must be harvested from the legs and arms for bypass construction on the heart. Deploying an inflatable blanket over a person may interfere with if not prevent the necessary access. Adapting the blanket to avoid interference by reducing its size may compromise its capacity to warm the person. Adapting the blanket to provide access by separable seals may extend and complicate the surgery due to need to integrate the operation and management of the blanket with surgical protocols.
One way to achieve the benefits of warming a person during cardiac surgery without the interference caused by a blanket is to utilize an inflatable convective pad which may be disposed beneath the person. The person is laid on the pad and the pad warms the person by convection of warmed air, and also by conduction and radiation, from beneath and around the person while leaving the chest and periphery uncovered. An inflatable convective pad is described in the assignee's U.S. Pat. No. 6,102,936. The assignee's Model 555 pediatric underbody blanket is another example of an inflatable convective pad. However, in spite of the access to necessary surgical sites that is available with an inflatable convective pad, there are drawbacks to its use in certain surgeries.
For example, in cardiac surgery the widely used “draw sheet” protocol interferes with effective operation of an inflatable convective pad. In this regard, in preparation for surgery, a sheet of material (called a “draw sheet”), typically between two and three feet in width and four to six feet in length, is centered transversely under a person and each end of the sheet is threaded between one arm and the adjacent side of the person. Each end is then brought over the bicep and dropped along the outside of its respective arm, tightened over the arm, and then pinned between the operating table mattress and the operating table. The draw sheet retains or immobilizes the arms against movement during surgery. When an inflatable convective pad is deployed for warming, the draw sheet itself, and the immobilized arms, press against the sides of the pad and restrict airflow through the device.
Also, many thoracic surgeries are performed on ischemic patients with impaired circulation to extremities. Feet especially exhibit the effects of low oxygen saturation in tissue resulting from poor blood flow. This condition is ischemia. Ischemic extremities are particularly vulnerable to injury from the combination of heat and pressure, and burns can result where feet press against an inflatable convective pad inflated with heated, pressurized air.